• 대한전자공학회논문지SD
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• 제40권4호
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• pp.27-33
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• 2003

최근, 원통형 DFB전송 구조들은 다양한 광 소자들과 결합하여 광통신용 필터로 널리 사용되고 있다. 이 원통형 Bragg 격자 구조들의 광 필터특성을 분석하기 위하여 본 논문에서는 Floquet-Babinet의 원리에 의존한 새롭고 쉬운 모드 전송선로 이론 (Modal Transmission-Line Theory)을 제시하였다. 수치해석 결과, 제안한 해석법은 원통형 DFB전송 구조들의 필터특성을 분석하기 위한 유용한 프로그래밍 알고리즘을 제공하고, 다층 원통형 주기 구조들의 전송특성을 분석하기 위하여 쉽게 발전시킬 수 있음을 보였다.

• 한국광학회지
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• 제15권4호
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• pp.349-354
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• 2004

XFP(10 Gb/s Small Form Factor Pluggable) 트랜시버 모듈에 사용되는 광송신 서브어셈블리(TOSA: Transmitter Optical Sub-assembly)를 열적, 전기적 측면에서 설계, 제작 및 평가하였다. 저가격이며 소형인 TOSA를 제작하기 위해서 바이어스 티 및 정합저항등을 AlN서브마운트 위에 집적하였다. 10 Gb/s의 초고속 전기 신호의 입력을 위해 CPW형 마이크로파 전송로를 스템 구조체내에 도입하였다. 소자의 전기적 특성 분석을 위해 서브마운트내에 실장되는 각종 전기광학 부품들과 스템 구조체들을 고속회로 모델링 하였다. 제작한 TOSA의 특성평가를 통해, 85$^{\circ}C$에서 11 GHz 이상의 -3 dB 대역폭을 얻을 수 있었다.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
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• pp.96-97
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• 2000

Incoherent broadband optical sources have been applied in various areas such as a light source for optical device characterization, fiber-optic gyroscopes$^{(1)}$ , and spectrum sliced light source in wavelength division multiplexing (WDM) system$^{(2)}$ . To utilize the inherent low loss in silica optical fibers, various types of incoherent light sources are being developed. Among the light sources, the amplified spontaneous emission (ASE) from a rare earth doped fiber has benefits in temperature stability, high output power, low polarization dependence over semiconductor diodes$^{(3)}$ . Recently erbium doped fibers (EDF) have been intensively researched for ASE sources as well as optical amplifiers$^{(4)}$ . The spectrum of ASE from an EDF, however, is limited in the 1520~1560 nm range in conventional configurations. In this letter we described a new broadband ASE source which included both the conventional ASE band of Er$^{3+}$ ion, 1520nm~1560nm and ASE band from Tm$^{3+}$ ions that extends the bandwidth further. For the first time, to the best knowledge of authors, a fiber ASE source based on the energy transfer between Er$^{3+}$ and Tm$^{3+}$ ions in the range of 1460~1550 nm, has been demonstrated using a single 980nm pump laser diode. (omitted)omitted)

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.236.1-236.1
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• 2014

Compounds of Ga, such as gallium oxide (Ga2O3) and gallium nitride (GaN), are of interest due to its unique properties in semiconductor application. In particular, GaN has the potentially application for optoelectronic device such as light-emitting diodes (LEDs) and laser diodes (LDs) [1]. Nanoparticle is an interesting material due to its unique properties compared to the bulk equivalents. In this report, we develop a synthesizing method for gallium nitride nanoparticle using non-thermal plasma. For gallium source, the gallium is heated by thermal conduction of tungsten boat which is heated by eddy current induced from RF current in antenna. Nitrogen source for nanoparticle synthesis are from inductively coupled plasma with N2 gas. The synthesized nano particles are analyzed using field-emission scanning microscope (FESEM), transmission electron microscope (TEM) and x-ray photoelectron spectroscopy (XPS). The synthesized particles are investigated and discussed in wide range of experiment conditions such as flow rate, pressure and RF power.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.134.2-134.2
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• 2014

Photonic crystal solar cells have the potential for addressing the disparate length scales in polymer photovoltaic materials, thereby confronting the major challenge in solar cell technology: efficiency. One must achieve simultaneously an efficient absorption of photons with effective carrier extraction. Unfortunately the two processes have opposing requirements. Efficient absorption of light calls for thicker PV active layers whereas carrier transport always benefits from thinner ones, and this dichotomy is at the heart of an efficiency/cost conundrum that has kept solar energy expensive relative to fossil fuels. This dichotomy persists over the entire solar spectrum but increasingly so near a semiconductor's band edge where absorption is weak. We report a 2-D, photonic crystal morphology that enhances the efficiency of organic photovoltaic cells relative to conventional planar cells. The morphology is developed by patterning an organic photoactive bulk heterojunction blend of Poly(3-(2-methyl-2-hexylcarboxylate) thiophene-co-thiophene) and PCBM via PRINT, a nano-embossing method that lends itself to large area fabrication of nanostructures. The photonic crystal cell morphology increases photocurrents generally, and particularly through the excitation of resonant modes near the band edge of the organic PV material. The device performance of the photonic crystal cell showed a nearly doubled increase in efficiency relative to conventional planar cell designs. Photonic crystals can also enhance performance of other optoelectronic devices including organic laser.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1962-1963
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• 2002

The hand-piece fiber optics is applied to medical appliances such as glaucoma theraphy to focus semiconductor laser on the affected parts efficiently. In this paper, we evaluate optical properties such as beam power and radius of a hand-piece probe by experiments and we also simulate the hand-piece optics by ray tracing method in order to study major parameters to optimize focalization ability. As results, we show experimental and simulation results of the hand-piece optics and also summarize several requirements that have to be considered in optimizing the hand-piece optics.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.309-309
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• 2012

Heteroepitaxial growth remains as one of the continuously growing interests, because the heterogeneous crystallization on different substrates is a common feature in the fabrication processes of many semiconductor materials and devices, such as molecular beam epitaxy, pulsed laser deposition, sputtering, chemical bath deposition, chemical vapor deposition, hydrothermal synthesis, vapor phase transport and so on [1,2]. By using the R.F. sputtering system, ZnO thin films were deposited on graphene 4 and 6 mono layers, which is grown on 400 nm and 600 nm $SiO_2$ substrates, respectively. The ZnO thin layer was deposited at various temperatures by using a ZnO target. In this experimental, the working power and pressure were $3{\times}10^{-3}$ Torr and 50 W, respectively. The base pressure of the chamber was kept at a pressure around $10^{-6}$ Torr by using a turbo molecular pump. The oxygen and argon gas flows were controlled around 5 and 10 sccm by using a mass flow controller system, respectively. The structural properties of the samples were analyzed by XRD measurement. The film surface and carrier concentration were analyzed by an atomic force microscope and Hall measurement system. The surface morphologies were observed using field emission scanning electron microscope (FE-SEM).

• 한국전기전자재료학회논문지
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• 제19권8호
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• pp.769-774
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• 2006

In this paper the ZnO thin films, which has used spotlight of next generation short wavelength LEDs and semiconductor laser were deposited based on RF magnetron sputtering is described. The temperature at substrate and work pressure, which has implemented in sputtering process of ZnO thin films were settle down at $100^{\circ}C$ and 15 mTorr respectively. The ZnO 5N has used target. The thickness of ZnO thin films was about $1.6{\mu}m$ which was measured by SEM analysis after the sputtering process. Structural properties of ZnO thin films by in-situ and atmosphere annealing were analyzed by XRD. Transformation of grain size and surface roughness were observed by AFM. XPS spectra showed that ZnO thin film had a peak positions corresponding to the $Zn_{2p}$ and the $O_{1s}$. As form above XPS, we confirmed that post-annealing condition changed the atom ratio of Zn/O and microstructure in ZnO thin films.

• 한국광학회지
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• 제17권3호
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• pp.209-215
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• 2006

협대역 천이영역을 갖는 원통형 격자전송구조 (Circular Bragg Grating: CBG) 가 최근 DWDM을 위한 광통신용 대역통과 필터로 널리 사용되고 있다. 이 원통형 Bragg 격자 구조들의 광 필터특성을 분석하기 위하여 본 논문에서는 Floquet-Babinet의 원리에 의존하는 새로운 해석적인 모드 전송선로 이른 (Modal Transmission-Line Theory: MTLT)을 제시하였다. 수치해석 결과, 제안한 해석법은 CBG의 필터특성을 분석하기 위한 유용한 프로그래밍 알고리즘을 제공하고, 다층 원통형 주기 구조들의 그 전송특성을 분석하기 위하여 쉽게 발전시킬 수 있음을 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.175-175
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• 2008

투명전극으로 사용되고 있는 Indium tin oxide (ITO) 박막은 전기적 전도도와 기판과의 접확성, 화학적 안정성, 광투과율 등의 특성과 함께 우수한 전기 광학적 거동을 보이고 있다. 그러나 ITO는 고가의 재료이기 때문에 대체 투명전극으로 Al을 도핑한 ZnO 박막의 연구가 활발히 진행되고 있다. ZnO:Al 박막은 chemical vapor deposition, reactive magnetron sputtering, electron-beam evaporation, pulsed laser deposition 등의 당양한 방법을 이용하여 증착하였다. 그러나 최근 낮은 온도에서 대면적의 균일성과 우수한 특성 때문에 atomic layer depositon (ALD) 방법을 이용하여 많은 연구가 진행되고 있으며, 이런 투명전극은 태양전지를 위해 연구되어지고 있다. 따라서 본 연구에서는 ALD 방법으로 Al의 도핑 양을 조절하여, ZnO:Al 박막을 제조하여 그 특성을 평가하고, 또한 ZnO TFT를 제작하여 발표하고자 한다. ZnO와 ZnO:Al 박막은 실리콘과 유리 기판 위에 ALD (Lucida-D200, NCD Technology) 장치로 증착하였다. DEZn, TMA, $H_2O$는 ZnO와 ZnO:Al 박막을 증착하기 위한 전구체와 반응가스로 사용하였다. 증착된 박막은 XRD와 HRTEM을 이용하여 결정구조와 미세구조를 분석하였다. AFM과 4-point probe를 이용하여 증착된 박막의 표면 거칠기와 면저항을 관찰하였다. semiconductor parameter 분석기를 이용하여 제작된 ZnO TFT를 평가하였다.